Restructured the project structure back to the way it was, there's no reasonable way to split the modules

src/NadekoBot/Modules/Utility/Quote/QuoteService.cs

@@ -0,0 +1,32 @@
+#nullable disable warnings
+using LinqToDB;
+using LinqToDB.EntityFrameworkCore;
+using Nadeko.Bot.Db.Models;
+
+namespace NadekoBot.Modules.Utility;
+
+public sealed class QuoteService : IQuoteService, INService
+{
+    private readonly DbService _db;
+
+    public QuoteService(DbService db)
+    {
+        _db = db;
+    }
+    
+    /// <summary>
+    /// Delete all quotes created by the author in a guild
+    /// </summary>
+    /// <param name="guildId">ID of the guild</param>
+    /// <param name="userId">ID of the user</param>
+    /// <returns>Number of deleted qutoes</returns>
+    public async Task<int> DeleteAllAuthorQuotesAsync(ulong guildId, ulong userId)
+    {
+        await using var ctx = _db.GetDbContext();
+        var deleted = await ctx.GetTable<Quote>()
+            .Where(x => x.GuildId == guildId && x.AuthorId == userId)
+            .DeleteAsync();
+
+        return deleted;
+    }
+}